Head actuators are used to move a recording head relative to a recording media. This recording head motion allows servo readers and read/write elements on the head to be aligned correctly to the media during track following read/write operations.
Typically, recording head positioning requirements are high bandwidth. That is, head position changes required to keep the head in the correct location on the media must be made quickly and accurately. There are a number of variables that are considered in the design of recording head actuators in order to maintain high bandwidth head positioning. One of these is the actuator's response to input frequencies. Out-of-plane resonances in the moving head can create dynamic instabilities that reduce the bandwidth of the head actuator. The result is a tape drive that does not meet its performance requirements.